Ampoule with a seal in two compression states

ABSTRACT

Ampoules for dispensing flowable substances and metering systems incorporating the same are described herein. An ampoule for a flowable substance includes an ampoule body comprising an interior space for receiving the flowable substance and an inner circumferential surface having a guide region and a sealing region. A piston may be disposed in the interior space of the ampoule body such that the piston is slidably displaceable along a direction of displacement. The piston includes at least one sealing element for forming a seal with the inner circumferential surface in a contact zone on the outer circumference of the sealing element. The sealing element has a first compression state when the contact zone is in the guide region and a second compression state when the contact zone is in the sealing region. A second blocking device prevents movement of the contact zone from the sealing region to the guide region.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.12/713,812 filed Feb. 26, 2010, now U.S. Pat. No. 8,197,451, which is acontinuation of International Application No. PCT/EP2008/007116 filedAug. 30, 2008, which claims priority to European Patent application EP07 017 173.1 filed Sep. 1, 2007.

TECHNICAL FIELD

The present specification relates to ampoules for flowable substances,and in particular, to ampoules for medically active liquids foradministration with an infusion or injection device, and to meteringsystems with ampoules as described herein.

BACKGROUND

WO 2000/71185 A1 discloses a medicament ampoule with a plastic ampoulebody in which a piston is initially held by the ampoule body with aclearance fit. After the piston and the interior space of the ampoulehave been sterilized, the piston is displaced into an adjacent region ofthe interior space of the ampoule body where the piston together withthe ampoule body forms a seal. The seal is broken by returning thepiston to its initial position.

Infusion pumps based on the syringe pump principle are used for numerousmedical applications to continuously supply medicaments at a constant ortemporally variable rate. One example thereof is the treatment ofdiabetes mellitus by the continuous subcutaneous infusion of insulin.Miniaturized infusion pumps which operate according to the syringeprinciple have been developed for this purpose. One such pump is known,for example, from EP 985419 B1.

WO 0160434 A1 discloses a piston for use in ampoules for infusion pumpsof this type. The piston has a basic body and a sealing element bondedto the basic body such as by glue, adhesive, welding, etc. In this case,the basic body is composed, for example, of a thermoplastic materialsuch as polypropylene and the sealing element is composed of athermoplastic elastomer such as Santoprene.

However, because of their specific properties, stoppers with sealingelements made of thermoplastic elastomers may not remain sealed for theentire required storage period of several years under changing climateconditions because they are permanently deformed under the pressureacting on them from the ampoule body. Furthermore, when an ampoule witha pressed-in stopper is stored for a relatively long period of time at ahigh storage temperature, a slow deformation of the ampoule body underthe pressure acting on it from the stopper (i.e., creep) generallyoccurs, which also has a disadvantageous effect on the seal.

Embodiments described herein provide an ampoule for a flowable substancethat overcomes these disadvantages.

SUMMARY

In one embodiment, an ampoule for a flowable substance is disclosed. Theampoule includes an ampoule body having an interior space for receivingthe flowable substance and an inner circumferential surface having aguide region and a sealing region. The guide region and the sealingregion are positioned along a longitudinal axis of the ampoule body. Apiston may be disposed in the interior space of the ampoule body suchthat the piston is slidably displaceable along the longitudinal axis ofthe ampoule body in a direction of displacement. The piston may includeat least one sealing element for forming a seal with the innercircumferential surface of the ampoule body in a contact zone on anouter circumference of the at least one sealing element. The ampoulealso includes a second blocking device which prevents movement of thecontact zone from the sealing region to the guide region. The at leastone sealing element has a first compression state when the contact zoneis in the guide region of the inner circumferential surface. The atleast one sealing element also has a second compression state when thecontact zone is in the sealing region such that the innercircumferential surface forms a fluidic seal with the at least onesealing element. When the at least one sealing element is in the secondcompression state, the at least one sealing element has a greater degreeof compression than when the at least one sealing element is in thefirst compression state. The interior space of the ampoule body can havea cross section which deviates from circularity in a directionperpendicular to the direction of displacement and along thelongitudinal axis of the ampoule body

In another embodiment, a metering system for a flowable substance isdisclosed. The metering system comprises an injection or diffusiondevice for dispensing the flowable substance from an ampoule having anampoule body, a piston and a second blocking device. The ampoule bodycan have a cross section which deviates from a circular shape. Theampoule body includes an interior space for receiving the flowablesubstance and an inner circumferential surface having a guide region anda sealing region. The guide region and the sealing region are positionedalong a longitudinal axis of the ampoule body. The inner circumferentialsurface can taper in from the guide region to the sealing region. Thepiston is disposed in the interior space of the ampoule body such thatthe piston is slidably displaceable along a longitudinal axis of theampoule body in a direction of displacement. The piston includes atleast one sealing element for forming a seal with the innercircumferential surface of the ampoule body in a contact zone on anouter circumference of the at least one sealing element. The at leastone sealing element has a first compression state when the contact zoneis in the guide region of the inner circumferential surface. The atleast one sealing element also has a second compression state when thecontact zone is in the sealing region such that the innercircumferential surface forms a fluidic seal with the at least onesealing element when the at least one sealing element is in the secondcompression state. The second blocking device prevents movement of thecontact zone from the sealing region to the guide region. The injectionor diffusion device is connectable to the piston of the ampoule toadvance the piston in the interior space in the direction ofdisplacement such that the flowable substance is dispensed from theampoule.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts an ampoule according to one or more embodiments shown anddescribed herein;

FIG. 2 depicts a longitudinal cross section of the ampoule of FIG. 1,with the sealing element in the first compression state;

FIG. 3 depicts a magnified view of a detail of the contact zone betweena sealing element and an inner circumferential surface of thelongitudinal cross section depicted in FIG. 2;

FIG. 4 depicts a magnified view of a detail of a first and secondblocking device of the longitudinal cross section depicted in FIG. 2;

FIG. 5 depicts a longitudinal cross section of an ampoule according toFIG. 1, with the sealing element in the second compression state;

FIG. 6 depicts an isometric view of an ampoule according to one or moreembodiments shown and described herein;

FIG. 7 depicts a longitudinal cross section of an ampoule according toFIG. 6, with the sealing element in the first compression state;

FIG. 8 depicts a radial cross section of the ampoule body in the sealingregion of an ampoule according to FIG. 6;

FIG. 9 depicts an isometric view of an ampoule comprising a firstpartial ampoule and a second partial ampoule according to one or moreembodiments shown and described herein;

FIG. 10 depicts a longitudinal cross section of an ampoule according toFIG. 9, with the sealing elements of the partial ampoules in the firstcompression state; and

FIG. 11 depicts an isometric view of a metering system with an ampoulecorresponding to FIGS. 6-8.

DETAILED DESCRIPTION

According to one embodiment, an ampoule has an ampoule body, theinterior space of which receives the flowable substance. Said substancemay be, for example, a low-viscosity liquid such as insulin or anothermedically active liquid, a high-viscosity liquid or else a pulverulentsubstance. The material used for the ampoule body is preferably glass ora thermoplastic, but the ampoule body may also be formed from anothersuitable material such as stainless steel or ceramic materials.

The ampoule may comprise a piston which has at least one sealing elementthat can be displaced along a direction of displacement in the interiorspace of the ampoule body. The direction of displacement corresponds tothe direction of movement of the piston in order to empty the substancefrom the interior space of the ampoule body. In one embodiment, thedirection of displacement corresponds to the longitudinal axis of theampoule body. In at least one contact zone which encircles the outercircumference of the at least one sealing element, the piston makescontact with the inner circumferential surface of the ampoule body suchthat the piston is compressed thereby. The piston can be manufactured,for example, from a thermoplastic elastomer or a pure elastomer.

In one embodiment, the piston comprises a basic body made of a differentmaterial than the sealing element. For example, the basic body may bemanufactured from a thermoplastic material of high rigidity, such aspolypropylene, and the sealing element may be manufactured from athermoplastic elastomer or pure elastomer of low Shore hardness such asSantoprene. With this construction, a high degree of rigidity (which isadvantageous for the piston) can be associated with a high degree ofelasticity for the sealing element. The sealing element can be formed,for example, by means of an O-ring and can be fitted into acorresponding groove in the basic body. Alternatively, two or moreO-rings can be used. In one embodiment, the basic body and sealingelement are bonded together such as with an adhesive, welding, glue,etc. Alternatively, the basic body and sealing element are formed as atwo component injection-molded part. In further embodiments, the basicbody and the sealing element are connected with a snap-in connection.

The inner circumferential surface of the ampoule body has a guide regionand a sealing region along the direction of displacement. Specifically,the cross section of the interior space of the ampoule body is formedwith the guide region in a plane transverse to the direction ofdisplacement such that the at least one sealing element has a firstcompression state when the contact zone is in the guide region. Thecross section of the interior space of the ampoule body is also formedwith the sealing region such that the at least one sealing element has asecond compression state when the contact zone is in the sealing region.When the sealing element is in the second compression state the sealingelement has a greater degree of compression than when the sealingelement is in the first compression state. In the second compressionstate, the inner circumferential surface of the ampoule body forms afluidic seal together with the sealing element. The guide region may beformed such that the inner circumferential surface does not compress thesealing element or only compresses it to such a slight extent that thesealing element is not plastically compressed when the contact zone isin the guide region. (In contrast to an elastic deformation, a plasticdeformation is permanently maintained even after the end of anapplication of force).

A measure of the deformation of the sealing element is its degree ofcompression which indicates the percentage of compression of the sealingelement with respect to its load-free extent. When thermoplasticelastomers are used for the sealing element, said elastomers should notbe compressed to more than 25% in the sealing region. In one embodimentan ampoule with a circular cylindrical cross section has an insidediameter in the sealing region of 6.5 mm and the load-free diameter ofthe sealing element is 6.9 mm. This results in a reduction in thediameter of the sealing element by 6.9 mm−6.5 mm=0.4 mm due tocompression, which, in this example, is 5.8%.

In one embodiment, a second blocking device is provided which preventsdisplacement of the contact zone out of the region of the secondcompression state of the sealing element opposite the initial directionof displacement. In this embodiment, once the contact zone between thesealing element and the inner circumferential surface of the ampoulebody has been displaced from the guide region into the sealing regionthereby forming a fluidic seal, the second blocking device prevents theseal from being broken by preventing the sealing element from beingwithdrawn from the sealing region.

The second blocking device can comprise at least one piston-side stop, asliding surface and a second ampoule-body-side stop.

In one embodiment, the inner circumferential surface of the ampoule bodytogether with the at least one sealing element does not form a seal withregard to a medium with a sterilizing effect and/or radiation with asterilizing effect when the at least one sealing element is in the firstcompression state. Accordingly, a medium with a sterilizing effectand/or radiation with a sterilizing effect can penetrate the interiorspace of the ampoule body when the at least one sealing element is inthe first compression state in order to sterilize the interior space ofthe ampoule body.

The ampoule body may have a transition region which connects theinterior space of the ampoule body in the guide region to the interiorspace of the ampoule body in the sealing region in a continuous manner,i.e. without jumps or edges.

Furthermore, for sealing reasons and in order to improve the guidance ofthe piston in the ampoule body, the sealing element and innercircumferential surface of the ampoule body can be formed in such amanner that, together with the inner circumferential surface of theampoule body, the sealing element includes two or more contact zonesand/or two or more sealing elements can be provided.

In one embodiment, the piston comprises at least one guide element whichis offset relative to the at least one sealing element in the directionof an opening of the ampoule body. In this embodiment, the guide elementmakes contact with the inner circumferential surface of the ampoulebody. This offset guide element prevents both tilting of the piston andinadvertent displacement of the piston in the ampoule body.

An ampoule according to the embodiments described herein may have adrawing-up device for displacing the piston opposite the direction ofdisplacement. The drawing-up device may be used when filling theampoule, to pull back the piston after the piston has been pushed allthe way into the ampoule. In one embodiment, the drawing-up device is apiston rod integrally formed with the piston itself. In anotherembodiment, the drawing-up device is in the form of a piston rod thatcan be releasably coupled to the piston.

In order to ensure a smooth movement of the piston in the interior spaceof the ampoule body and low frictional forces, the ampoules of theembodiments described herein may include a viscous lubricant, such assilicone oil, which forms a lubricating film on the innercircumferential surface of the ampoule body. As an alternative or inaddition, the friction can also be reduced by other measures. Forexample, the inner circumferential surface of the ampoule body and/or ofthe sealing element may be coated with a layer of silicone or Teflon.

The piston of an ampoule according to the embodiments described hereinmay comprise a coupling device for coupling the piston to an advancingunit of an injection or infusion device. In this case, the couplingdevice comprises a plane surface to which a compressive force can beapplied by a pressure plate of the advancing unit. In anotherembodiment, the coupling device comprises an external thread or a rackwhich can be engaged with a lock nut or a gear wheel of an advancingunit.

The ampoule body may be provided with at least one outlet opening whichis used both for filling the ampoule and for emptying the ampoule. Inone embodiment, the at least one outlet opening is arranged coaxiallywith respect to an axis of symmetry of the ampoule body.

In a further embodiment, an outlet opening is arranged transversely withrespect to the direction of displacement. In one embodiment, the outletopening leads into a Luer cone. In another further embodiment, theoutlet opening is closed by means of a septum which can be pierced by ahollow cannula in order to vent, fill and empty the interior space ofthe ampoule.

When the contact zone is located between the inner circumferentialsurface of the ampoule and the sealing element in the guide region,slight compression of the sealing element indicates that the piston fitsloosely in the ampoule body. In order to prevent an inadvertent removalof the piston from the ampoule body in this state, a first blockingdevice may be provided. The blocking device prevents withdrawal of thecontact zone from the region of the first compression state of thesealing element opposite the direction of displacement.

The first blocking device can comprise at least one piston-side stop, asliding surface and a first ampoule-body-side stop.

When an ampoule has a first blocking device, the first and the secondblocking devices may be similar in design to each other. In particular,the at least one piston-side stop of the first blocking device may bethe at least one piston-side stop of the second blocking device. Inaddition, the at least one sliding surface of the first blocking devicemay be the at least one sliding surface of the second blocking device.

A piston-side stop which is utilized in conjunction with both the firstblocking device and the second blocking device and a sliding surfacewhich is common to a first blocking device and a second blocking devicemay be designed as a catch which is arranged on a radially resilientspring arm surrounding the piston and extending in a direction towardsan open end side of the ampoule body. In this embodiment, the wall ofthe ampoule body has at least one first cutout and at least one secondcutout which is offset in the direction of displacement R with respectto the first cutout, with the first ampoule-body-side stop being formedby the wall of the at least one first cutout and the secondampoule-body-side stop being formed by the wall of the at least onesecond cutout. In the unloaded state of the spring arm, the at least onecatch can project into the at least one first cutout and, alternatively,into the at least one second cutout.

Furthermore, the at least one spring arm can be designed in such amanner that the inner circumferential surface of the ampoule body can bedeformed such that the at least one catch presses resiliently againstthe inner circumferential surface of the ampoule. This can improve theguidance of the piston in the interior space of the ampoule body and,because of the pressure, can counteract an inadvertent displacement ofthe piston.

The interior space of the ampoule body can have differentcross-sectional shapes perpendicular to the direction of displacement ofthe piston; in one embodiment, the cross-sectional shape is circular. Inother embodiments, the ampoule body has a cross section which deviatesfrom the circular shape; in particular, in one embodiment, it has anelliptical shape. In a further embodiment, the interior space of theampoule body has at least one pair of mutually opposite, parallelboundary surfaces. The latter can be connected via curved, for examplesemi-cylindrical, circumferential surfaces. An ampoule-body shape whichdeviates from the cylindrical shape may be particularly advantageous foruse in injection or infusion systems.

An ampoule according to the embodiments described herein may be providedin sterile packaging, with the at least one sealing element being in thefirst compression state. In this case, removal of the piston from theampoule body may be prevented by means of a first blocking device.Before the ampoule is filled, the piston is displaced in the directionof displacement, as a result of which the contact zone between the atleast one sealing element and the inner circumferential surface of theampoule is displaced from the guide region via the transition regioninto the sealing region, with the at least one sealing element beingtransferred into the second compression state. Further movement of thepiston in the direction of displacement vents the interior space of theampoule. At the same time, a viscous lubricant present in the interiorspace of the ampoule body may be distributed uniformly over the innercircumferential surface of the ampoule body by movement of the piston.If the at least one outlet opening is closed by a septum, the latter ispierced by a hollow cannula before the movement of the piston.

Venting of the interior space is followed by filling the interior spacewith the active substance liquid. The filling preferably taking placethrough the at least one outlet opening, which in this case, is used asa filling opening. If the at least one outlet opening is closed by aseptum, the latter is pierced with a hollow cannula (which has alreadybeen used for the venting) or with a further hollow cannula. Filling isperformed by pulling the piston opposite the direction of displacementwith the aid of the drawing-up device, which produces a negativepressure between the outlet opening and piston in the previously ventedinterior space of the ampoule body. The negative pressure causes theactive substance liquid to be sucked into the interior space of theampoule body. As an alternative, it may also be possible to press theactive substance liquid by means of positive pressure through the outletopening into the interior space of the ampoule body, with the activesubstance liquid displacing the piston opposite the direction ofdisplacement.

The embodiments described herein also relate to ampoules for a flowablesubstance which comprise at least one first partial ampoule according toembodiments described herein and a second partial ampoule according tothe embodiments described herein. This facilitates an overall flatdesign of an ampoule having a relatively large capacity and a smallinternal cross section with improved rigidity. In some embodiments, thepartial ampoules are identical and, in particular, have an identicalinterior space. However, depending on the space conditions, for examplein an injection or infusion device, the individual ampoules may alsohave different cross sections. The partial ampoules may be arranged withrespect to each other in such a manner that they have a common directionof displacement. In this case, the pistons of the partial ampoules maybe connected to each other with a connecting piece integrally formedwith the pistons such as when the connection piece and pistons areinjection-molded. However, in other embodiments, the directions ofdisplacement may also be at an angle with respect to each other. Inparticular, the individual ampoules may also be arranged with respect toeach other in such a manner that their directions of displacement areopposed to each other. The at least two partial ampoules preferably havea common outlet opening. However, a plurality of outlet openings, forexample one outlet opening per partial ampoule, may also be provided.

Embodiments described herein also relate to metering systems for aflowable substance, in particular for the infusion of insulin or othermedically active substances. Such a system comprises an ampouleaccording to the embodiments described herein and an injection orinfusion device which is operatively coupled to the ampoule. Inparticular, the injection or infusion device can fully or partiallyaccommodate the ampoule.

Furthermore, the metering system may comprise an adapter which can bereleasably coupled to the injection or infusion device, and an injectionor infusion cannula, with the adapter coupling the outlet opening of theampoule fluidically to the injection or infusion cannula and forming astop for securing the ampoule in the direction of displacement. In thiscase, the injection or infusion cannula can be coupled such that itdirectly adjoins the adapter or can be coupled to the adapter via acatheter. In one embodiment, the outlet opening of the ampoule comprisesa septum which is pierced by a cannula surrounded by the adapter.

The adapter may be coupled to the injection or infusion device byrelative movement between adapter and injection or infusion devicetransversely with respect to the direction of displacement, with therelative movement at the same time fluidically coupling the outletopening of the ampoule to the adapter.

The adapter can furthermore have a monitoring device for monitoring themetering, for example in the form of a pressure sensor, a pressureswitch or a flow sensor.

The injection or infusion device preferably comprises an advancing unitfor the controlled displacement of the piston in the direction ofdisplacement.

In particular, the advancing unit can comprise a piston rod which canretract into the ampoule through an ampoule opening facing the advancingunit, and can thus displace the piston in a controlled manner within theampoule. As an alternative, the piston may also comprise a threaded rodor a rack which can be in engagement with a lock nut surrounded by theadvancing unit, or with a toothed wheel.

The embodiments described herein may be explained with reference toexemplary embodiments illustrated in the appended drawings.

Referring to FIGS. 1 and 2, an ampoule according to at least oneembodiment described herein is schematically depicted. The cylindricalampoule body 10 is a thermoplastic material which is injection-molded toform an interior space 15 in which a flowable substance such as insulinor another medicinal substance, may be received. The piston 25 is atwo-component injection-molded part comprising a thermoplastic basicbody 45 and a sealing element 30 which is placed onto the basic body 45.The piston 25 is positioned in the ampoule body 10 such that the sealingelement 30 is in contact with the inner circumferential surface 20 ofthe ampoule in a contact zone K. That end surface of the basic body 45which points towards the opening 57 of the ampoule body 10 is designedas a plane surface 27 by which a compressive force can be transmitted tothe piston 25, thus resulting in displacement of the piston in adirection of displacement R. The direction of displacement R correspondsto the longitudinal axis of the ampoule.

Referring to FIGS. 2-4, the sealing element 30 makes contact with theinner circumferential surface 20 of the ampoule body 10 in the guideregion 35. FIG. 3 shows the transition between guide region 35 andsealing region 40. In order to prevent removal of the piston 25 from theampoule body 10, a first blocking device, which is illustrated in FIG.4, is provided. For this purpose, the ampoule body 10 has, on itscircumference, first cutouts 51, 51′, the edges of which face theopening 57 of the ampoule body forming first ampoule-body-side stops 50,50′. The piston 25 has radially resilient spring arms 54, 54′ whichprotrude perpendicularly from it and end in catches 52, 52′. The catches52, 52′ each comprise a piston-side stop 55, 55′ and a sliding surface60, 60′. During assembly, the piston 25 is introduced from the opening57 into the ampoule body 10 in the direction of displacement R. In theprocess, the spring arms 54, 54′ spring out of their relaxed inoperativeposition in the spring direction F, F′ radially outwards towards theampoule axis and the sliding surfaces 60, 60′ slide over the edge 53 ofthe inner circumferential surface of the ampoule body. As soon as thecatches 52, 52′ enter the first cutouts 51, 51′ during furtherdisplacement of the piston 25 in the direction of displacement R, thecatches 52 move opposite the spring direction F, F′ into a relaxedposition such that they project into the first ampoule-body-side cutouts51, 51′. When the piston 25 is moved opposite the direction ofdisplacement R, the piston-side stops 55, 55′ engage the firstampoule-body-side stops 50, 50′, and prevent further movement of thepiston 25 in the direction of the opening 57. In contrast, displacementof the piston 25 in the direction of displacement R remains possible asthe sliding surfaces 60, 60′ contact the edges 59, 59′ of the firstcutouts 51 which lie opposite the first ampoule-body-side stops 50, 50′and, in the process, displace the spring arms 54, 54′ in the springdirection F, F′.

Further movement of the piston 25 in the direction of displacement Rmoves the contact zone K from the guide region 35 into the sealingregion 40 where the interior space 15 of the ampoule body 10 has asmaller interior diameter. In this position, the sealing element 30 isin a second compression state as shown in FIG. 5. In order to preventjamming or even possible damage to the sealing element 30 when thecontact zone K is displaced from the guide region 35 into the sealingregion 40, the two regions are connected by a continuous transitionregion 37. In the case of a cylindrical ampoule cross section, the innercircumferential surface 20 of the ampoule body 10 in the transitionregion 37 is a cylindrical truncated cone, the diameter of which tapersfrom the inside diameter of the interior space 15 of the ampoule in theguide region 35 to the inside diameter of the interior space 15 of theampoule in the sealing region 40. In other embodiments the ampoule maybe formed with a contour which smoothly connects (i.e., a transitionwithout defined edges) the guide region 35, to the sealing region 40, inthe transition region 37. A displacement of the contact zone K oppositethe direction of travel R out of the sealing region 40 into the guideregion 35 results in a loss of the seal between the inside diameter ofthe interior space and the ampoule and should be prevented. Accordingly,a second blocking device, the operation of which is analogous to thefirst blocking device, is provided with second cutouts 66, 66′ andsecond ampoule-body-side stops 65, 65′. The second cutouts 66, 66′ areoffset in relation to the first cutout 51, 51′ in the direction ofdisplacement R. The spring arms 54, 54′ with catches 52, 52′ work inconjunction with the first blocking device and the second blockingdevice, and therefore the operation of the piston-side stops 55, 55′ andthe sliding surfaces 60, 60′ for both blocking devices is similar.

Alternatively, other constructions may be possible for the blockingdevices. For example, the inner circumferential surface 20 of theampoule body 10 may be formed with two pairs of catches which are offsetwith respect to each other in the direction of displacement R whilecorresponding cutouts are respectively formed in the radially resilientspring arms 54, 54′.

Further movement of the piston in the direction of displacement R causesthe catches 52, 52′ to press resiliently against the innercircumferential surface 20 of the ampoule body 10 due to the springforce of the spring arms 54, 54′. In addition to the friction betweensealing element 30 and inner circumferential surface 20 in the secondcompression state of the sealing element 30, this interaction betweenthe catches 52, 52′ of the spring arms 54, 54′ and the innercircumferential surface 20 of the ampoule body 10 constitutes protectionagainst inadvertent displacement of the piston 25 in the interior space15 of the ampoule body 10. Specifically, displacement of the piston 25results in a sliding frictional force between the inner circumferentialsurface 20 and the catches 52, 52′ in a direction opposite thedisplacement. At the same time, the contact between the innercircumferential surface 20 and the catches 52, 52′ prevents the piston25 from tilting in the ampoule body 10. Accordingly, the catches 52, 52′act as guide elements for the piston as they press resiliently againstthe inner circumferential surface 20 of the ampoule body 10.

To ensure a symmetrical introduction of force into the piston 25, thefirst blocking device and the second blocking device are each present induplicate and are offset by 180° with respect to each other on thecircumference of the ampoule. Alternatively, the first and secondblocking devices may be present in triplicate and offset by 120° oranother angular orientation other than 180°.

The interior space 15 of the ampoule body is fluidly coupled to anoutlet opening 70 which is provided with an end surface 71 for couplingto a conventional cannula or to a catheter such as a Luer cone.

Referring now to FIGS. 6-8, a second embodiment of an ampoule isschematically depicted. Specifically, FIG. 7 shows a longitudinalsection of the ampoule of FIG. 6 with the sealing element 30 in thefirst compression state while FIG. 8 shows a radial cross section of theampoule body 10 in the sealing region 40. This embodiment differs fromthe embodiment illustrated in FIGS. 1 to 5 in the cross sectional shapeof the ampoule body 10. Specifically, the interior space 15 of theampoule body 10 is defined by two plane-parallel surfaces 11, 11′ andtwo cylindrical circumferential surfaces 12, 12′ connecting the surfaces11, 11′. This results in a flatter profile compared to a cylindricalampoule, which is advantageous in particular for use in injection orinfusion systems. Furthermore, in this embodiment, the outlet opening 70is arranged transversely with respect to the direction of displacementR, which leads to a smaller axial dimension compared to an axialarrangement of the outlet opening. A fluidically tight septum 72 whichcan be pierced with a hollow cannula is located in the outlet opening.

Referring collectively to FIGS. 6-8, starting from the opening 57, theplane-parallel walls 13, 13′ (FIG. 8) have U-shaped cutouts 58, 58′(FIG. 6) in the guide region 35 (FIG. 7). Referring now to FIG. 7, thesefacilitate grasping the piston 25 or a drawing-up device and may bereleasably connected to the piston 25 such that the piston can bedisplaced in a direction opposite the direction of displacement R. Thisis required if liquid is to be guided through the outlet opening 70 bymeans of the piston 25 being pulled back opposite the direction ofdisplacement R.

Referring to FIGS. 9 and 10, another embodiment of an ampoule isschematically depicted. Specifically, FIG. 9 shows an ampoule whichcomprises a first partial ampoule 100 and a second partial ampoule 200while FIG. 10 shows a longitudinal cross section of the ampoule of FIG.9.

An ampoule corresponding to this embodiment comprises two individualpartial ampoules 100 and 200. The partial ampoules 100, 200 areconstructed according to the single ampoule embodiments shown anddescribed herein, with the partial ampoules 100 and 200 being arrangedparallel to each other and being connected via a web such that they havea common direction of displacement R. In one embodiment, the piston 125of the first partial ampoule is coupled to the piston 225 of the secondpartial ampoule via a connecting piece 101 in such a manner that adisplacement in the common direction of displacement R or opposite thecommon direction of displacement R takes place jointly for piston 125and piston 225. The end surface 102 of the connecting piece 101 canserve at the same time for the transmission of a compressive force tothe pistons 125, 225, resulting in a displacement of piston 125 andpiston 225 in the direction of the displacement R.

In order to improve guidance of the piston in the ampoule(s), thesealing element 130 is configured in such a manner that it has twocontact zones K11 and K12, which are offset with respect to each other,with the inner circumferential surface 120 of the first ampoule body 110in the direction of displacement R, and the sealing element 230 isconfigured in such a manner that it has two contact zones K21 and K22,which are offset with respect to each other, with the innercircumferential surface 220 of the second ampoule body 210 in thedirection of displacement R. The ampoule body 110 and the ampoule body210 have a common outlet opening 70 which is transversely oriented withrespect to the direction of displacement R. A fluidically tight septum72 which can be pierced with a hollow cannula is located in the commonoutlet opening 70.

In this embodiment, the sealing elements 130 and 230 together with thebasic bodies 145 and 245 of the pistons 125 and 225 and the connectingpiece 101 are designed as an integral two-component injection-moldedpart.

The operation of the first blocking device and the second blockingdevice in FIGS. 9 and 10 generally correspond to the embodiments of theampoule shown and described in FIGS. 1-8.

The basic bodies 145 and 245 work together with the connecting piece 101as a drawing-up device for displacement of the pistons 125 and 225opposite the direction of displacement R.

Referring to FIGS. 6-8 and 11, FIG. 11 shows a metering system formedicaments such as insulin. The metering system comprises an ampoulebody 10 corresponding to the ampoule shown in FIG. 8, and an infusionsystem 310 which entirely or partially accommodates the ampoule body 10.The infusion system comprises an advancing unit 315 in the form of aspindle drive with a DC motor or stepping motor 316, a reduction anddeflection gearing 317 and a piston rod 318. The piston rod 318 can beextended in a controlled manner out of the reduction and deflectiongearing 317 in the direction of displacement R in order to empty out amedicament contained in ampoule and, in the process, exert a compressiveforce by means of a pressure plate (not illustrated) on the planesurface 27 of the piston 25, this resulting in a controlled displacementof the piston 25 in the direction of displacement R. Furthermore, theinfusion device 310 comprises an electronic controller 311, a userinterface 312 and a power supply 313. The user interface can comprise analphanumeric display (not illustrated) for providing information to theuser, and also one or more keying elements (not illustrated) by which auser may input information into the infusion device 310.

An adapter 320 fluidically couples the outlet opening 70 of the ampouleto an injection or infusion cannula (not illustrated). The adapter 320furthermore comprises an extension arm 322 which projects over the endsurface 71 of the ampoule body 10 and thus forms a stop for the ampoulebody 10, the stop fixing the ampoule in the direction of displacement Rand constituting a counter-bearing for the controlled displacement ofthe piston 25 by the advancing unit 315.

The components of the metering system are assembled as follows: (1) Theampoule body 10 which is filled with insulin is inserted into theinfusion device 310 counter to the direction of displacement R. (2) Theadapter 320 is releasably coupled to the infusion device 310 bydisplacement of the adapter in the direction S which is transverse tothe direction of displacement R. To guide the adapter 320, the adapteris fitted with a dovetail 321 which is fastened to the adapter 320. Thedovetail 321 corresponds to a groove (not illustrated) on the infusiondevice 310. The ampoule body 10 is also fluidly coupled to the adapter320 by the same movement in the direction S. To facilitate fluidcoupling, the adapter 320 comprises a hollow cannula (not visible inFIG. 11), the longitudinal axis of which corresponds to the direction S.The hollow cannula of the adapter 320 pierces the septum 72 arranged inthe outlet opening 70. The outlet opening 325 of the adapter 320 may befluidly coupled to an infusion catheter which is integral with theadapter, or may be fluidly coupled to an infusion catheter with afluidic coupling. As an alternative, the outlet opening 325 can befluidly coupled to an infusion cannula which is integral with theadapter or connected to the adapter via a fluidic coupling.

Furthermore, the adapter 320 can comprise a monitoring device formonitoring the metering, such as a pressure or flow sensor, or theadapter can contain a flexible pressure transmission membrane whichtransmits the fluidic pressure to a pressure sensor located in theinfusion device 310.

What is claimed is:
 1. An ampoule for a flowable substance comprising:an ampoule body comprising an interior space for receiving the flowablesubstance and an inner circumferential surface having a guide region anda sealing region, wherein the guide region and the sealing region arepositioned along a longitudinal axis of the ampoule body; a pistondisposed in the interior space of the ampoule body such that the pistonis slidably displaceable along the longitudinal axis of the ampoule bodyin a direction of displacement, the piston comprising at least onesealing element for forming a seal with the inner circumferentialsurface of the ampoule body in a contact zone on an outer circumferenceof the at least one sealing element; a second blocking device whichprevents movement of the contact zone from the sealing region to theguide region, wherein: the second blocking device comprises a secondampoule-body-side stop, a piston-side stop and a sliding surface; the atleast one sealing element has a first compression state when the contactzone is in the guide region of the inner circumferential surface; the atleast one sealing element has a second compression state when thecontact zone is in the sealing region such that the innercircumferential surface forms a fluidic seal with the at least onesealing element and when the at least one sealing element is in thesecond compression state, the at least one sealing element has a greaterdegree of compression than when the at least one sealing element is inthe first compression state; and the interior space of the ampoule bodyhas a cross section which deviates from circularity in a directionperpendicular to the direction of displacement and along thelongitudinal axis of the ampoule body.
 2. The ampoule according to claim1, wherein the piston is a two component injection-moulded partcomprising a basic body and the at least one sealing element, whereinthe basic body is formed from a thermoplastic material and the at leastone sealing element is formed from a thermoplastic elastomer.
 3. Theampoule according to claim 1, wherein the ampoule comprises a firstblocking device which prevents removal of the piston from the ampoulebody in a direction opposite the direction of displacement.
 4. Theampoule according to claim 3, wherein the first blocking devicecomprises a first ampoule-body-side stop, a piston-side stop and asliding surface.
 5. The ampoule according to claim 4, wherein: thesecond blocking device comprises a second ampoule-body-side stop, apiston-side stop and a sliding surface; and the piston-side stop of thefirst blocking device is the piston-side stop of the second blockingdevice.
 6. The ampoule according to claim 5, wherein the sliding surfaceof the first blocking device is the sliding surface of the secondblocking device.
 7. The ampoule according to claim 6, wherein: thepiston comprises at least one radially resilient spring arm extendingfrom the piston towards an opening of the ampoule body, the at least oneradially resilient spring arm having a catch forming the piston-sidestop and the sliding surface; and the ampoule body has a first cutoutand a second cutout offset from the first cutout in the direction ofdisplacement, wherein the first ampoule-body-side stop is formed by awall of the first cutout, the second ampoule body-side stop is formed bya wall of the second cutout, and the catch projects into the firstcutout and into the second cutout when the at least one radiallyresilient spring arm is in an unloaded state.
 8. The ampoule accordingto claim 7, wherein the catch presses against the inner circumferentialsurface of the ampoule body when the at least one radially resilientspring arm is deformed by the inner circumferential surface of theampoule body.
 9. The ampoule according to claim 1, wherein the innercircumferential surface has a transition region disposed between theguide region and the sealing region.
 10. The ampoule according to claim1, wherein the ampoule body has at least one outlet opening.
 11. Theampoule according to claim 1, wherein the at least one sealing elementcomprises at least two contact zones.
 12. The ampoule according to claim1, wherein the piston comprises a guide element which is offset from theat least one sealing element in a direction of an opening of the ampoulebody, wherein the guide element makes contact with the innercircumferential surface of the ampoule body.
 13. The ampoule accordingto claim 1, wherein the piston comprises a coupling device for couplingthe piston to an advancing drive of an injection or infusion device. 14.The ampoule according to claim 1, wherein the at least one sealingelement and the inner circumferential surface of the ampoule body do notseal with regard to a medium with a sterilizing effect when the at leastone sealing element is in the first compression state.
 15. The ampouleaccording to claim 1, wherein the ampoule comprises a drawing-up devicefor displacing the piston in a direction opposite the direction ofdisplacement.
 16. A metering system for a flowable substance comprisingan injection or diffusion device for dispensing the flowable substancefrom an ampoule having an ampoule body, a piston and a second blockingdevice, wherein: the ampoule body has a cross section which deviatesfrom a circular shape, and comprises an interior space for receiving theflowable substance and an inner circumferential surface having a guideregion and a sealing region, wherein the guide region and the sealingregion are positioned along a longitudinal axis of the ampoule body andthe inner circumferential surface tapers in from the guide region to thesealing region; the piston is disposed in the interior space of theampoule body such that the piston is slidably displaceable along alongitudinal axis of the ampoule body in a direction of displacement,the piston comprising at least one sealing element for forming a sealwith the inner circumferential surface of the ampoule body in a contactzone on an outer circumference of the at least one sealing element,wherein: the at least one sealing element has a first compression statewhen the contact zone is in the guide region of the innercircumferential surface; the at least one sealing element has a secondcompression state when the contact zone is in the sealing region suchthat the inner circumferential surface forms a fluidic seal with the atleast one sealing element when the at least one sealing element is inthe second compression state; the second blocking device preventsmovement of the contact zone from the sealing region to the guide regionand comprises a second ampoule-body-side stop, a piston-side stop and asliding surface; and the injection or diffusion device is connectable tothe piston of the ampoule to advance the piston in the interior space inthe direction of displacement such that the flowable substance isdispensed from the ampoule.